Astrophytum asterias (star cactus) is a small, spineless cactus. Each plant usually has a single low, dome-shaped stem that becomes flat or depressed during dry conditions. In the wild, star cactus grows to 7 cm tall and 15 cm in diameter. Plants are green to grayishgreen or goldish-brown, patterned with whitish to yellowish circular scales. Each normally has 8 triangular ribs separated by narrow grooves. The areoles follow a central line down each rib, bearing tufts of short, whitish hairs.
The pale yellow flowers with orange-red bases appear in mid-March through May (Fig. 1) (Benson 1982; Damude and Poole 1990).

Star cactus was listed as endangered by the US Fish and Wildlife Service (USFWS) in 1993 due to its few populations and high degree of threat from collecting. It is also listed in the Convention on International Trade in Endangered Species (CITES) Appendix I. Star cactus is an extremely popular collector’s item. Even though it is easily grown from seed, plants continue to be taken from the wild.

Endangered Astrophytum asterias

(Star cactus), Starr County, Texas

Lophophora williams II

(Peyote), Starr County, Texas

Grandmother and younger plants showing variation in number of ribs.

Lophophora williamsii (peyote) resembles star cactus in its size, shape and lack of spines. However, peyote is bluish-green and lacks the tiny whitish scales found on star cactus. Peyote has 5-13 (most often exactly 5, 8 or 13) ribs, the number increasing with age. Star cactus, in contrast, generally has 8 ribs throughout life. Peyote’s ribs may extend toward the base in a spiral conformation not seen in star cactus. Mature specimens of Lophophora williamsii may have pronounced tubercles, which give the ribs an irregular appearance not observed in Astrophytum asterias.

Peyote in flower

Starr County, Texas

The flowers of peyote appear pale pink in color (Fig. 3).
The outer tepals are white with a green stripe down the midline, but only the inner tepals, which are white with a pink stripe down the midline, are visible from above when the flowers are fully open.

Peyote

The flowers of peyote appear pale pink in color. The outer tepals are white with a green stripe down the midline, but only the inner tepals, which are white with a pink stripe down the midline, are visible from above when the flowers are fully open.

Peyote

The flowers of peyote appear pale pink in color. The outer tepals are white with a green stripe down the midline, but only the inner tepals, which are white with a pink stripe down the midline, are visible from above when the flowers are fully open.

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